Re: Light level monitoring - to add to Homevision/Comfort

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

>
> Hi Gary,
>
> Is it inside or outside that you wish to monitor ? Do you already have
> by any chance any of the C-Bus sensors with inbuilt light level
> reporting ?  Some of the ceiling PIR's include this as a bonus feature
> (5753PEIRL), you never know, you might already have something.
>
> I'd need to check about support within the xAP gateway for these -
> can't remember if they can report or at least control via a lighting
> compatible application or if they're on measurement.  I think they are
> compatible as they can be used without logic to achieve much the
> effect you want.
>
> I have played with this and it took a bit of refining to get it
> working acceptably.  I use sensors within the room now (xAP reporting
> but  IDRANet hardware not C-Bus ) and also have outside light level
> reporting.  The lights can vary in brightness to maintain an inside
> minimum  lighting level but in practice they were mostly on/off in the
> not brightly illuminated room.  Ramp times reduced the switching
> annoyance.  I also had to set up some logic to avoid this happening
> when unoccupied and/or at weird times like at dawn if it got brighter
> and then darker again.  Hysteresis was important too and I found that
> the lights were not sufficiently bright to avoid the room going a lot
> dimmer in overcast periods.  I think you need a lot of reserve
> brightness (wattage)  to actually maintain a constant brightness if
> that's your goal.
>
> Here's a couple of graphs for yesterday .. one inside and one
> outside.  The shape of the curves is quite different and I was
> surprised how steep the outside light changes were.   If you look
> closely on the inside graph at around 8.30PM you'll see the very small
> difference the lights coming on made in their overall contribution,
> but this was in more of a mood lit room (i.e. dimmer lighting).
>
> Inside http://tinyurl.com/ch8qu3m
> Outside http://tinyurl.com/cx4cfhq
>
>
> K
>



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